It really varies on what you are planning to feed your horse.
I have ten horses and my feed bill on average is as follows -
$120 for hard feeds and suplements a week.
$150 a week on hay. Most of my horses are on adlib hay, and the fatties are fed a carefully weighed amount.
You can contact some of the feed manufacturers and ask them if they can do up a diet for you. I have recently had three done and found the service very helpful. When you contact them they will need information about your horse so it is worth having all the info in front of you - breed of horse, height, weight, type of grazing, work load
I hope that helps a little bit
